Pembrolizumab-induced vasculitis demonstrated by FDG-PET/CT

Our plain-English summary of Pembrolizumab-induced vasculitis demonstrated by FDG-PET/CT, by T. Vu, S.R. O'Brien, S.X. Ma, et al (Radiology Case Reports, 2024).

The study

• Authors: T. Vu, S.R. O'Brien, S.X. Ma, K.M. Sundaram, A.R. Pantel
• Journal: Radiology Case Reports
• Published: 2024;19(9):3959-3961
• Type of article: Case report
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

A 76-year-old man with a history of malignant pleural mesothelioma treated with pembrolizumab underwent FDG-PET/CT for restaging. The images demonstrated FDG uptake overlying the right hepatic and splenic artery, which were new from the previous FDG-PET/CT 2.5 years prior before the patient started pembrolizumab, suspicious for vasculitis. A follow-up MRI supported the diagnosis with evidence of celiac, splenic, common hepatic, and right hepatic artery involvement. Pembrolizumab was discontinued and the patient received a short course of oral glucocorticoids. Subsequent FDG-PET/CT performed 14 months after initiation of treatment for vasculitis demonstrated resolution of vasculitis. Immune checkpoint inhibitors can cause vasculitis, which can be recognized on FDG-PET/CT and lead to appropriate treatment.

© 2024 The Authors. Published by Elsevier Inc. on behalf of University of Washington.

In plain English

This case report described one patient: a 76-year-old man with malignant pleural mesothelioma. He had been treated for 10 months with pembrolizumab, an immune checkpoint inhibitor drug, without new or changed symptoms. A routine restaging FDG-PET/CT scan, which shows areas that take up a radioactive sugar tracer, found uptake along the right hepatic artery (SUVmax of 9.8) and the splenic artery (SUVmax of 5.7). The authors considered this suspicious for vasculitis, an inflammation of blood vessels. A follow-up MRI showed thickened walls of the common hepatic, right hepatic, splenic and celiac arteries, suggestive of medium-vessel vasculitis. Pembrolizumab was stopped, steroid treatment was started, and other cancer drugs followed. A PET/CT scan 14 months later showed the artery uptake had completely resolved even though the mesothelioma had progressed. The authors said this supported pembrolizumab-related vasculitis. They concluded that immune checkpoint inhibitors can cause vasculitis that can be detected on FDG-PET/CT and MRI. A single case does not show how often this happens. The article does not discuss asbestos exposure.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: case report (single patient)
• Who was studied: one 76-year-old man with malignant pleural mesothelioma receiving pembrolizumab; place and dates of care not stated
• Exposure: pembrolizumab (an immune checkpoint inhibitor) for 10 months; asbestos exposure is not discussed
• Main results:
  • In this patient, FDG-PET/CT showed uptake along the right hepatic artery (SUVmax 9.8) and splenic artery (SUVmax 5.7), suspicious for vasculitis
  • Follow-up MRI showed thickened walls of the common hepatic, right hepatic and splenic arteries, plus enhancement and wall thickening of the splenic and celiac arteries, suggestive of medium-vessel vasculitis
  • A PET/CT taken 14 months after pembrolizumab was stopped and steroid treatment and other systemic therapies were started showed complete resolution of the artery uptake, even though the mesothelioma had progressed
• The authors' conclusion: The authors concluded that immune checkpoint inhibitors can cause vasculitis, which can be detected on FDG-PET/CT and MRI, and that recognizing the imaging findings can help direct patient care.

Topics

Medical terms in this study, explained in our Lexicon: Pembrolizumab (Keytruda), Pleural Mesothelioma, checkpoint inhibitors.

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